We are trying to upsert Payment records to Salesforce but we get Contact: ID value of incorrect type error.
We are using PaymentID as external Id for Payments.
Contact is a lookup field on Payment and we are sending Contact Member ID (External ID on contact)
So when I send Contact Member ID 12345 on payment, it gives Contact: ID value of incorrect type error. How do I solve this error?
Note: We are sending data from our internal system, so our system doesn't hold salesforce IDs. So we can only use Contact Member ID as lookup.